Robert A Boyajian

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Middle cerebral artery (MCA) flow velocity was continuously monitored during smoking in an observational study (n = 14) using transcranial Doppler (TCD) ultrasonography. Cerebral autoregulatory vasodilator capacitance under inspired CO2 challenge was also measured before smoking and at peak smoking effect. Several puffs on a single lighted cigarette over a(More)
Ultrasound-derived volumetric flow analysis may be useful in answering questions of basic physiological interest in the cerebrovascular circulation. Using this technique, the authors have sought to describe quantitatively the complete concurrent flow relations among all four arteries supplying the brain. The aim of this study of normal subjects was to(More)
OBJECTIVE The goal was to determine whether magnetic source imaging could identify a signature for cortical involvement in patients with amyotrophic lateral sclerosis (ALS), and to determine whether the method might provide insight into functional abnormalities associated with the disease process. DESIGN Spontaneous brain activity recordings from(More)
Magnetoencephalography (MEG) is a sensitive technique that can detect and map cortical electrophysiologic activations with high spatial (mm) and temporal (msecs) resolutions. We used 148-channel whole-head MEG to record the activation sequence for the somatosensory and motor cortical network during cued hand movements in a healthy 39-yr-old subject. The(More)
Neuroimaging shows that both global and focal neurologic deficits after cardiac surgery share an acute, often multifocal, embolic cerebral infarction etiology; yet, analyses of stroke risk factors historically have emphasized the focal deficits. We test if consolidating encephalopathy and coma with focal deficits affects four stroke risk factors and a dummy(More)
Humoral biomarkers of inflammation appear to correlate with future cardiovascular events warranting investigation of more specific associations between phenotypic subclasses of circulating cellular immunity and atherogenic progression of carotid stenosis. Retrospective study of carotid stenosis progression based on archived serial carotid duplex(More)
BACKGROUND AND PURPOSE Today's vascular laboratory technology offers broad applications throughout vascular medicine. We explore the diagnostic work-up and management of selected peripheral vascular diseases by benchmarking the institutional mix of invasive and noninvasive technology utilization and associated cost burdens. METHODS Specialized diagnostic(More)
Tha pathophysiology of brain injury in patients undergoing cardiopulmonary bypass remains unclear despite several decades of inquiry. The advent of noninvasive high-resolution brain and cerebrovascular imaging by magnetic resonance, computed tomography, and pulsed Doppler ultrasonography now permits in vivo assessment of pathophysiological mechanisms.(More)
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